Dimensions: 80X75X20Mm / 3.15"X2.95"X0.79" On/Off Switch. Trs Easy To Use: Press The S Or M Key To Set The Second Or Minute; Press St/Sp Key To Start/Stop The Timer; Simultaneously Press The M + S Button And The Reset 00:00 Button. Power: 1X Aaa Battery. (Not Included). Countup Function: When Time 00:00, Press St/Sp Key, Will Count From 00:00> >00:01 >> 00:02... Countdown Function: After The Required Set Time, Such As 99:59, Press St/Sp Button, Will Count Down From 99:59 >> 99:58 >> 99:57 ... When The Countdown Has Finished, The Timer Will Sound "Didididi.... Didididi..." To Remind You Press Any Button To Stop Ringing. Loud, Alarm Sound, Can Hear From Another Room. Magnetic Mount And Retractable Stand. Attractive Design. High Quality Materials. Memory (Remembers The Last Setting Used): Press The St/Sp Button To Restore The Last Setting Used. Timer Can Count Up And Down So Can Be Used As A Stopwatch As Well As A Countdown Timer, Ideal For Cooking Food, Homework, Exercises, Sports, Games, Downtime (For Children), Office And Classroom Activities. The Maximum Time Set Is 99 Minutes And 59 Seconds. If The Alarm Is Not Manually Stopped, It Will Continue To Ring For 1 Minute. The Timer Will Remember The Last Setting, Which Is Useful For Repetitive Activities.